I take an evening to sit down and configure/learn the controls on the camera. With a new lens I'll take some 'real world' test shots in and around the house but nothing involving test charts or the like. Then I'll usually take it out on a foto-shoot the next weekend, always nice to use new gear
Any fault should quickly become apparent if you start using the stuff before the return period is over.
5D3, 5D2, Sony NEX-6 | SY14mm f/2.8, Ʃ20mm f/1.8, 35mm f/2, Ʃ35mm f/1.4A, 50mm f/1.8 I, Ʃ50mm f/1.4 EX, 100mm f/2.8L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: Ʃ19mm f/2.8 EX DN, Ʃ30mm f/2.8 EX DN, 16-50 OSS, 55-210 OSS | 2x FT-QL, AE-1P, FD(n) & FL primes.